Problem: Evaluate the following expression when $y = 5$ and $x = 9$. $3$ $y$ $ + 8$ $x$ $ + 9$
Explanation: Substitute $5$ for ${y}$ and $9$ for ${x}$ $ = 3{(5)} + 8{(9)} + 9 $ $ = 15 + 72 + 9 $ $ = 96$